Ah.... that's how that works. I remember that being buggy once.
Or I could never quite figure out how it worked.
The "works if the highlighted Thought is linked with the active Thought"-part comes completely out of left field. Cause it also works when I hover over a link, unlinking the hovered-link, no matter what the link is connecting.
Description says "remove the selected Link".
I am a man of many skills. Mindreading isn't one of them, though.
I'm facepalming so hard right now.
Ya know what I ended up doing?
When I wanted to remove all parents from a Thought or remove all Jumps, I'd put the mouse-cursor hovering over the exact right position, so that when Link>Unlink took effect, I'd immediately hover over the next link, so I can use the command again. Or rather I tried removing children from parents that way. But it was random to me whether the Plex would show the Parent or the Child.
I'm happy to finally know this and now knowing the way it's implemented, it's even reasonably fast.
Now that I know what it's doing, I can even control which Thought disappears on the Plex, whereas before I was very often frustrated by having to search the one to jump back to it.
Seriously though..... 🙁